Chapter 2 Adequate Nutrients Within Calorie Needs

OVERVIEW

Many Americans consume more calories than they need without meeting
recommended intakes for a number of nutrients. This circumstance means that most
people need to choose meals and snacks that are high in nutrients but low to
moderate in energy content; that is, meeting nutrient recommendations must go
hand in hand with keeping calories under control. Doing so offers important
benefitsnormal growth and development of children, health promotion for people
of all ages, and reduction of risk for a number of chronic diseases that are
major public health problems.

Based on dietary intake data or evidence of public health problems, intake
levels of the following nutrients may be of concern for:

At the same time, in general, Americans consume too many calories and too
much saturated and trans fats, cholesterol, added sugars, and salt.

KEY RECOMMENDATIONS

Consume a variety of nutrient-dense foods and beverages within and
among the basic food groups while choosing foods that limit the intake of
saturated and trans fats, cholesterol, added sugars, salt, and alcohol.

Meet recommended intakes within energy needs by adopting a balanced
eating pattern, such as the USDA Food Guide or the DASH Eating Plan.

Key Recommendations for Specific Population Groups

People over age 50. Consume vitamin B12 in its crystalline form (i.e.,
fortified foods or supplements).

Women of childbearing age who may become pregnant. Eat foods high in heme-iron and/or consume iron-rich plant foods or iron-fortified foods
with an enhancer of iron absorption, such as vitamin C-rich foods.

Women of childbearing age who may become pregnant and those in the
first trimester of pregnancy. Consume adequate synthetic folic acid daily
(from fortified foods or supplements) in addition to food forms of folate
from a varied diet.

DISCUSSION

Meeting Recommended Intakes Within Energy Needs

A basic premise of the Dietary Guidelines is that food guidance
should recommend diets that will provide all the nutrients needed for growth and
health. To this end, food guidance should encourage individuals to achieve the
most recent nutrient intake recommendations of the Institute of Medicine,
referred to collectively as the Dietary Reference Intakes (DRIs). Tables of the
DRIs are provided at
http://www.iom.edu/Object.File/Master/21/372/0.pdf.

An additional premise of the Dietary Guidelines is that the
nutrients consumed should come primarily from foods. Foods contain not only the
vitamins and minerals that are often found in supplements, but also hundreds of
naturally occurring substances, including carotenoids, flavonoids and
isoflavones, and protease inhibitors that may protect against chronic health
conditions. There are instances when fortified foods may be advantageous, as
identified in this chapter. These include providing additional sources of
certain nutrients that might otherwise be present only in low amounts in some
food sources, providing nutrients in highly bioavailable forms, and where the
fortification addresses a documented public health need.

Two examples of eating patterns that exemplify the Dietary Guidelines
are the DASH Eating Plan and the USDA Food Guide. These two similar eating
patterns are designed to integrate dietary recommendations into a healthy way to
eat and are used in the Dietary Guidelines to provide examples of how
nutrient-focused recommendations can be expressed in terms of food choices. Both
the USDA Food Guide and the DASH Eating Plan differ in important ways from
common food consumption patterns in the United States. In general, they include:

Less refined grains, total fats (especially cholesterol, and saturated and
trans fats), added sugars, and calories.

Both the USDA Food Guide and the DASH Eating Plan are constructed across a
range of calorie levels to meet the nutrient needs of various age and gender
groups. Table 1 provides food intake recommendations, and
table 2 provides
nutrient profiles for both the DASH Eating Plan and the USDA Food Guide at the
2,000-calorie level. These tables illustrate the many similarities between the
two eating patterns. Additional calorie levels are shown in appendixes
A-1 and
A-2 for the USDA Food Guide and the DASH Eating Plan. The exact amounts of foods
in these plans do not need to be achieved every day, but on average, over time.
Table 3 can aid in identification of an individual's caloric requirement based
on gender, age, and physical activity level.

Variety Among and Within Food Groups

Each basic food group5 is the major
contributor of at least one nutrient while making substantial contributions of
many other nutrients. Because each food group provides a wide array of nutrients
in substantial amounts, it is important to include all food groups in the daily
diet.

Both illustrative eating patterns include a variety of nutrient-dense foods
within the major food groups. Selecting a variety of foods within the gran,
vegetable, fruit, and meat groups may help to ensure that an adequate amount of
nutrients and other potentially beneficial substances are consumed. For example,
fish contains varying amounts of fatty acids that may be beneficial in reducing
cardiovascular disease risk (see ch. 6).

Nutrient-Dense Foods

Nutrient-dense foods are those foods that provide substantial amounts of
vitamins and minerals (micronutrients) and relatively few calories. Foods that
are low in nutrient density are foods that supply calories but relatively small
amounts of micronutrients, sometimes none at all. The greater the consumption of
foods or beverages that are low in nutrient density, the more difficult it is to
consume enough nutrients without gaining weight, especially for sedentary
individuals. The consumption of added sugars, saturated and trans fats, and
alcohol provides calories while providing little, if any, of the essential
nutrients. (See ch. 7 for additional information on added sugars,
ch. 6 for
information on fats, and ch. 9 for information on alcohol.)

Selecting low-fat forms of foods in each group and forms free of added
sugarsin other words nutrient-dense versions of foodsprovides individuals a
way to meet their nutrient needs while avoiding the overconsumption of calories
and of food components such as saturated fats. However, Americans generally do
not eat nutrient-dense forms of foods. Most people will exceed calorie
recommendations if they consistently choose higher fat foods within the food
groupseven if they do not have dessert, sweetened beverages, or alcoholic
beverages.

If only nutrient-dense foods are selected from each food group in the amounts
proposed, a small amount of calories can be consumed as added fats or sugars,
alcohol, or other foodsthe discretionary calorie allowance. Appendixes
A-2 and
A-3 show the maximum discretionary calorie allowance that can be accommodated at
each calorie level in the USDA Food Guide. Eating in accordance with the USDA
Food Guide or the DASH Eating Plan will also keep intakes of saturated fat,
total fat, and cholesterol within the limits recommended in
chapter 6.

Nutrients of Concern

The actual prevalence of inadequacy for a nutrient can be determined only if
an Estimated Average Requirement (EAR) has been established and the distribution
of usual dietary intake can be obtained. If such data are not available for a
nutrient but there is evidence for a public health problem associated with low
intakes, a nutrient might still be considered to be of concern.

Based on these considerations, dietary intakes of the following nutrients may
be low enough to be of concern for:

Efforts may be warranted to promote increased dietary intakes of potassium,
fiber, and possibly vitamin E, regardless of age; increased intakes of calcium
and possibly vitamins A (as carotenoids) and C and magnesium by adults; efforts
are warranted to increase intakes of calcium and possibly magnesium by children
age 9 years or older. Efforts may be especially warranted to improve the dietary
intakes of adolescent females in general. Food sources of these nutrients are
shown in appendix B.

Low intakes of fiber tend to reflect low intakes of whole grains, fruits, and
vegetables. Low intakes of calcium tend to reflect low intakes of milk and milk
products. Low intakes of vitamins A (as carotenoids) and C and magnesium tend to
reflect low intakes of fruits and vegetables. Selecting fruits, vegetables,
whole grains, and low-fat and fat-free milk and milk products in the amounts
suggested by the USDA Food Guide and the DASH Eating Plan will provide adequate
amounts of these nutrients.

Most Americans of all ages also need to increase their potassium intake. To
meet the recommended potassium intake levels, potassium-rich foods from the
fruit, vegetable, and dairy groups must be selected in both the USDA Food Guide
and the DASH Eating Plan. Foods that can help increase potassium intake are
listed in table 5 (ch. 5) and appendix
B-1.

Most Americans may need to increase their consumption of foods rich in
vitamin E (α-tocopherol) while decreasing their intake of foods high in energy
but low in nutrients. The vitamin E content in both the USDA Food Guide and the
DASH Eating Plan is greater than current consumption, and specific vitamin
E-rich foods need to be included in the eating patterns to meet the recommended
intake of vitamin E. Foods that can help increase vitamin E intake are listed in
appendix B-2, along with their calorie content. Breakfast cereal that is
fortified with vitamin E is an option for individuals seeking to increase their
vitamin E intake while consuming a low-fat diet.

In addition, most Americans need to decrease sodium intake. The DASH Eating
Plan provides guidance on how to keep sodium intakes within recommendations.
When using the USDA Food Guide, selecting foods that are lower in sodium than
others is especially necessary to meet the recommended intake level at calorie
levels of 2,600/day and above. Food choices that are lower in sodium are
identified in chapter 8.

Considerations for Specific Population Groups

People Over 50 and Vitamin B12

Although a substantial proportion of individuals over age 50 have reduced
ability to absorb naturally occurring vitamin B12, they are able to absorb the
crystalline form. Thus, all individuals over the age of 50 should be encouraged
to meet their Recommended Dietary Allowance (RDA) (2.4 µg/day) for vitamin B12 by
eating foods fortified with vitamin B12 such as fortified cereals, or by taking
the crystalline form of vitamin B12 supplements.

Women and Iron

Based on blood values, substantial numbers of adolescent females and women of
childbearing age are iron deficient. Thus, these groups should eat foods high in
heme-iron (e.g., meats) and/or consume iron-rich plant foods (e.g., spinach) or
iron-fortified foods with an enhancer of iron absorption, such as foods rich in
vitamin C (e.g., orange juice). Appendix B-3 lists foods that can help increase
iron intake and gives their iron and calorie content.

Women and Folic Acid

Since folic acid reduces the risk of the neural tube defects, spina bifida,
and anencephaly, a daily intake of 400 µg/day of synthetic folic acid (from
fortified foods or supplements in addition to food forms of folate from a varied
diet) is recommended for women of childbearing age who may become pregnant.
Pregnant women should consume 600 µg/day of synthetic folic acid (from fortified
foods or supplements) in addition to food forms of folate from a varied diet. It
is not known whether the same level of protection could be achieved by using
food that is naturally rich in folate.

Special Groups and Vitamin D

Adequate vitamin D status, which depends on dietary intake and cutaneous
synthesis, is important for optimal calcium absorption, and it can reduce the
risk for bone loss. Two functionally relevant measures indicate that optimal
serum 25-hydroxyvitamin D may be as high as 80 nmol/L. The elderly and
individuals with dark skin (because the ability to synthesize vitamin D from
exposure to sunlight varies with degree of skin pigmentation) are at a greater
risk of low serum 25-hydroxyvitamin D concentrations. Also at risk are those
exposed to insufficient ultraviolet radiation (i.e., sunlight) for the cutaneous
production of vitamin D (e.g., housebound individuals).

Fluid

The combination of thirst and normal drinking behavior, especially the
consumption of fluids with meals, is usually sufficient to maintain normal
hydration. Healthy individuals who have routine access to fluids and who are not
exposed to heat stress consume adequate water to meet their needs. Purposeful
drinking is warranted for individuals who are exposed to heat stress or perform
sustained vigorous activity (see ch. 4).

Flexibility of Food Patterns for Varied Food Preferences

The USDA Food Guide and the DASH Eating Plan are flexible to permit food
choices based on individual and cultural food preferences, cost, and
availability. Both can also accommodate varied types of cuisines and special
needs due to common food allergies. Two adaptations of the USDA Food Guide and
the DASH Eating Plan are:

Vegetarian Choices

Vegetarians of all types can achieve recommended nutrient intakes through
careful selection of foods. These individuals should give special attention to
their intakes of protein, iron, and vitamin B12, as well as calcium and vitamin
D if avoiding milk products. In addition, vegetarians could select only nuts,
seeds, and legumes from the meat and beans group, or they could include eggs if
so desired. At the 2,000-calorie level, they could choose about 1.5 ounces of
nuts and 2/3 cup legumes instead of 5.5 ounces of meat, poultry, and/or fish.
One egg, ½ ounce of nuts, or
¼ cup of legumes is considered equivalent to 1
ounce of meat, poultry, or fish in the USDA Food Guide.

Substitutions for Milk and Milk Products

Since milk and milk products provide more than 70 percent of the calcium
consumed by Americans, guidance on other choices of dietary calcium is needed
for those who do not consume the recommended amount of milk products. Milk
product consumption has been associated with overall diet quality and adequacy
of intake of many nutrients, including calcium, potassium, magnesium, zinc,
iron, riboflavin, vitamin A, folate, and vitamin D. People may avoid milk
products because of allergies, cultural practices, taste, or other reasons.
Those who avoid all milk products need to choose rich sources of the nutrients
provided by milk, including potassium, vitamin A, and magnesium in addition to
calcium and vitamin D (see app. B). Some non-dairy sources of calcium are shown
in appendix B-4. The bioavailability of the calcium in these foods varies.

Those who avoid milk because of its lactose content may obtain all the
nutrients provided by the milk group by using lactose-reduced or low-lactose
milk products, taking small servings of milk several times a day, taking the
enzyme lactase before consuming milk products, or eating other calcium-rich
foods. For additional information, see appendixes B-4 and
B-5 and NIH
Publication No. 03-2751.6

Amounts of various food groups that are recommended each day or each week in
the USDA Food Guide and in the DASH Eating Plan (amounts are daily unless
otherwise specified) at the 2,000-calorie level. Also identified are equivalent
amounts for different food choices in each group. To follow either eating
pattern, food choices over time should provide these amounts of food from each
group on average.

e Since eggs are high in cholesterol, limit egg yolk
intake to no more than 4 per week; 2 egg whites have the same protein content as 1 oz of meat.

f The oils listed
in this table are not considered to be part of discretionary calories because
they are a major source of the vitamin E and polyunsaturated fatty acids,
including the essential fatty acids, in the food pattern. In contrast, solid
fats (i.e., saturated and trans fats) are listed separately as a source of
discretionary calories.

TABLE 2. Comparison of Selected Nutrients in the Dietary Approaches to Stop
Hypertension (DASH) Eating Plana, the USDA
Food Guideb, and Nutrient Intakes Recommended
Per Day by the Institute of Medicine (IOM)c

Estimated nutrient levels in the DASH Eating Plan and the USDA Food Guide at
the 2,000-calorie level, as well as the nutrient intake levels recommended by
the Institute of Medicine for females 19-30 years of age.

Estimated amounts of calories needed to maintain energy balance for various
gender and age groups at three different levels of physical activity. The
estimates are rounded to the nearest 200 calories and were determined using the
Institute of Medicine equation.

a
These levels are based on Estimated Energy Requirements (EER) from the Institute
of Medicine Dietary Reference Intakes macronutrients report, 2002, calculated by
gender, age, and activity level for reference-sized individuals. "Reference
size," as determined by IOM, is based on median height and weight for ages up to
age 18 years of age and median height and weight for that height to give a BMI
of 21.5 for adult females and 22.5 for adult males.

c Moderately active means
a lifestyle that includes physical activity equivalent to walking about 1.5 to 3
miles per day at 3 to 4 miles per hour, in addition to the light physical
activity associated with typical day-to-day life

e The calorie ranges shown
are to accommodate needs of different ages within the group. For children and
adolescents, more calories are needed at older ages. For adults, fewer calories
are needed at older ages.